Change GetInputDeviceState to return InputDeviceState_NoInputHandler instead of InputDeviceState_Invalid

Rename "_Disconnected" to "_Unplugged"

stepmania/src/RageInput.cpp

@@ -151,7 +151,7 @@ InputDeviceState RageInput::GetInputDeviceState( InputDevice id )
 		}
 	}
 
-	return InputDeviceState_Invalid;
+	return InputDeviceState_NoInputHandler;
 }
 
 RString RageInput::GetDisplayDevicesString() const